With the increasing occurrence of counterfeit or illegal products, industry has been seeking techniques for generating permanent identification of components or parts. When conventionally applied, character strings representing serial numbers or like product identification can be altered and serialized sets of them may be mimicked. Accordingly, when such false or illegal character strings of identification are combined with fully copied trade dress, trademarks and product shaping and sizing, counterfeiting entities can glean substantial illegal profits. These profits are at the loss of the genuine producer which also incurs losses due to warranty repairs carried out with respect to the apparently valid products and losses of good will as may be associated with the distribution of lower quality counterfeit merchandise. Further liabilities may be imposed upon industry where successfully counterfeited products, having apparently legal serial number or the like identification, exhibit defects which become the subject matter of legal liability. It is important for the original and genuine manufacturer to have a technique for encrypting its serial number identification procedures and the like such that the counterfeiter cannot readily carry out description procedures. Of course, a secure encrypting system for progressive numbering or identification will be of considerable value in the production of lottery tickets and the like.
Permanent marking of products with indented or stamped characters has been utilized in industry, but until recently, this approach has been considered of limited value, particularly where serial number identification is required in conjunction with large volume production. Classic stamping approaches have, for example, utilized dies which carry a collection of full formed characters. These characters may be positioned in a die carrier which is manipulated to define a necessarily short message. Over the recent past, a computer driven system for rapidly creating substantial character strings by pin indentation has been successfully introduced to industry. This system, marketed under the trade designation "PINSTAMP" and described in U.S. Pat. No. 4,506,999 utilizes marker pins which are controllably actuted to form dot-like indentation defined pixels within a given matrix of available pixels to form characters. The latter characters being permanently indented in the product surface marked, are removable essentially only by grinding or like procedures. For most applications of these character strings, however, there further exists a requirement that the numerical and alphabetical characters of a given message string so marked upon a product surface be man readable. Thus, where such products are stolen, a valid serial number may be altered by the addition of indentations to change character designations, for example, from a "P" to a "R".
Another aspect of product identification or marking, particularly associated with the noted indentation techniques, is concerned with defective original marking. For example, where incorrect alignment occurs between the piecepart marking surface and the marking mechanism, a significant portion of a given character may not be formed, resulting in a loss of readability. Characteristically, the portions of the characters which are lost due to defective stamping techniques tend to occur either at the top or bottom region of the character configuration. Such losses also may occur in conjunction with product thievery where attempts are made to remove the characters of a character string by grinding procedures or the like. Very often, authorities are able to recover at least a portion of the originally indented character identification information, for instance by using chemical etching procedures or the like. Thus, if particular portions of a formed character are sufficiently unique in and of themselves, such analytic identification techniques become more promising and enjoy substantially more reliable evidenciary value.